Last Modified: Sunday, February 3, 2013 at 4:10 p.m.

So when the garden's prized ficus microcarpa — commonly referred to as banyans — showed signs of stress from a new bug two years ago, horticulture director Mike McLaughlin initially took a wait-and-see approach.

McLaughlin watched as a cascade of green leaves fell from the expansive canopy. Dead foliage crunched under foot and blanketed a wide section of the gardens.

As the leaf drops continued, McLaughlin's worry grew.

"These are important trees," he said.

Marie Selby planted the trees on her bayfront estate turned namesake botanical gardens more than 70 years ago. They have since become a popular backdrop for outdoor weddings and countless other social events.

The leafy ficus are such an important fixture at Selby, the attraction is staking its future on them. Plans for a new "Children's Rainforest Garden" feature elevated walkways into the banyan canopy.

But by last summer the trees "were damn near naked," McLaughlin said.

"You could see the sky and the ground was solid with green leaves," he said.

McLaughlin knew he had to act.

Gardens infested

The Selbys, Marie and her oil tycoon husband William, were part of the first wave of wealthy snowbirds who helped popularize Sarasota as a winter enclave for the well-to-do.

They built a home on seven acres pinched between Sarasota Bay and Hudson Bayou in the early 1920s. The property became a botanical gardens in 1975.

Selby was a gardening enthusiast and founding member of Sarasota's first garden club. Her exotic ficus flourished over the years, sending out dozens of aerial roots that give the trees their unique, spindly-trunk appearance.

As the trees grew, their upper branches merged and blotted out the sky. The thick canopy serves as a shady resting spot for gardens visitors.

But it also attracted an aphid-like insect known as a whitefly. A native of Asia, the pest hitched a ride to Miami five years ago. It has spread to 16 Florida counties, including Sarasota and Manatee.

The whitefly has scaly, pinhead-sized offspring that feast on the sap of certain ficus trees, including microcarpa. Large, and with pronounced aerial roots, microcarapa are commonly called banyans, although another ficus species is considered to be the only true banyan.

Florida discourages new microcarpa plantings because the trees are considered an invasive species, but mature trees are often prized by homeowners for their hardiness and grandeur. The Selby ficus are popular with gardens visitors.

"People have a connection with these particular trees," McLaughlin said.

Big problem

Selby's ficus whitefly problems began just as the state was facing an onslaught of complaints about the pest.

Homeowners began clamoring for help, said Greg Hodges with the Florida Department of Agriculture and Consumer Services.

Ficus are commonly used in landscaping throughout South Florida. The Miami area has been particularly hard hit by the ficus whitefly and two other species of whitefly that are new to Florida in recent years.

"The outcry from residents in South Florida got to the point where we really had to do something," Hodges said.

One of the whiteflies feasts on a much broader array of species than ficus, including palms and other popular landscaping plants.

The impact on ornamental landscapes is so extensive that Florida researchers received an emergency grant from the U.S. Department of Agriculture to study the problem.

A state website — www.flwhitefly.org — lists the symptoms of infestation and recommends treatments.

"These pests are huge nuisances," said Catherine Mannion, a researcher with the University of Florida agriculture extension office in Homestead. "They can be very damaging to plants."

Infested ficus trees and hedges seek relief by shedding and regrowing their leaves, a stressful undertaking that weakens the plant. Branches can also die off.

McLaughlin hoped that the Selby trees would fight through the infestation. He views chemical insecticides as a last resort.

It is unusual for the ficus whitefly to kill large trees, but a weak tree could succumb to disease.

When the leaf drops continued, Selby staff decided the risk of waiting was too great.

Saving the trees

The treatment was not simple, though.

Insecticide leaf sprays were impractical for such large trees with so many leaves, and the benefits are short-lived. Leaching the chemicals down to the tree roots could contaminate the soil and Sarasota Bay.

An attempt to inject treatments directly into the trunks failed. Ficus sap is highly pressurized; the trees spit out their medicine like a sick child.

McLaughlin shifted to a concentrated spray, applying it in measured amounts to the tree trunks. The chemicals absorb through the bark.

So far, so good, he says.

McLaughlin gathered a handful of fallen leaves and examined them under a hand-held microscope recently. None had signs of infestation.

A healthy leaf canopy has returned over the last few months.

The treatment should keep the ficus whitefly at bay for a year or more. What happens after that is hard to say.

The infestation could return. More treatments may be inevitable. Or the pest could become less pervasive, with predators taking notice and a natural balance settling in.

Selby has the expertise and resources to keep the pest in check. McLaughlin's long-term prognosis for the trees is good.

"I bet they'll outlive us," he said.

Homeowners may have a more difficult time saving their trees.

Selby donors stepped up to cover the cost of treatments, which ran into the thousands of dollars.

"There are systemic insecticides that work fairly well on the ficus whitefly but if the homeowner has a few trees or a long hedge it can become difficult for them to afford," Mannion said.

Mannion is doing research to identify the whiteflies' natural predators and other treatment methods.

<p><em>SARASOTA</em> - The staff at Marie Selby Botanical Gardens tries not to overreact when a new pest appears.</p><p>Insect infestations often run their course. Natural predators settle in. Plants bounce back.</p><p>So when the garden's prized ficus microcarpa — commonly referred to as banyans — showed signs of stress from a new bug two years ago, horticulture director Mike McLaughlin initially took a wait-and-see approach.</p><p>McLaughlin watched as a cascade of green leaves fell from the expansive canopy. Dead foliage crunched under foot and blanketed a wide section of the gardens.</p><p>As the leaf drops continued, McLaughlin's worry grew.</p><p>"These are important trees," he said.</p><p>Marie Selby planted the trees on her bayfront estate turned namesake botanical gardens more than 70 years ago. They have since become a popular backdrop for outdoor weddings and countless other social events.</p><p>The leafy ficus are such an important fixture at Selby, the attraction is staking its future on them. Plans for a new "Children's Rainforest Garden" feature elevated walkways into the banyan canopy.</p><p>But by last summer the trees "were damn near naked," McLaughlin said.</p><p>"You could see the sky and the ground was solid with green leaves," he said.</p><p>McLaughlin knew he had to act.</p><p><b>Gardens infested</b></p><p>The Selbys, Marie and her oil tycoon husband William, were part of the first wave of wealthy snowbirds who helped popularize Sarasota as a winter enclave for the well-to-do.</p><p>They built a home on seven acres pinched between Sarasota Bay and Hudson Bayou in the early 1920s. The property became a botanical gardens in 1975.</p><p>Selby was a gardening enthusiast and founding member of Sarasota's first garden club. Her exotic ficus flourished over the years, sending out dozens of aerial roots that give the trees their unique, spindly-trunk appearance.</p><p>As the trees grew, their upper branches merged and blotted out the sky. The thick canopy serves as a shady resting spot for gardens visitors.</p><p>But it also attracted an aphid-like insect known as a whitefly. A native of Asia, the pest hitched a ride to Miami five years ago. It has spread to 16 Florida counties, including Sarasota and Manatee.</p><p>The whitefly has scaly, pinhead-sized offspring that feast on the sap of certain ficus trees, including microcarpa. Large, and with pronounced aerial roots, microcarapa are commonly called banyans, although another ficus species is considered to be the only true banyan.</p><p>Florida discourages new microcarpa plantings because the trees are considered an invasive species, but mature trees are often prized by homeowners for their hardiness and grandeur. The Selby ficus are popular with gardens visitors.</p><p>"People have a connection with these particular trees," McLaughlin said.</p><p><b>Big problem</b></p><p>Selby's ficus whitefly problems began just as the state was facing an onslaught of complaints about the pest.</p><p>Homeowners began clamoring for help, said Greg Hodges with the Florida Department of Agriculture and Consumer Services.</p><p>Ficus are commonly used in landscaping throughout South Florida. The Miami area has been particularly hard hit by the ficus whitefly and two other species of whitefly that are new to Florida in recent years.</p><p>"The outcry from residents in South Florida got to the point where we really had to do something," Hodges said.</p><p>One of the whiteflies feasts on a much broader array of species than ficus, including palms and other popular landscaping plants.</p><p>The impact on ornamental landscapes is so extensive that Florida researchers received an emergency grant from the U.S. Department of Agriculture to study the problem.</p><p>A state website — www.flwhitefly.org — lists the symptoms of infestation and recommends treatments.</p><p>"These pests are huge nuisances," said Catherine Mannion, a researcher with the University of Florida agriculture extension office in Homestead. "They can be very damaging to plants."</p><p>Infested ficus trees and hedges seek relief by shedding and regrowing their leaves, a stressful undertaking that weakens the plant. Branches can also die off.</p><p>McLaughlin hoped that the Selby trees would fight through the infestation. He views chemical insecticides as a last resort.</p><p>It is unusual for the ficus whitefly to kill large trees, but a weak tree could succumb to disease. </p><p>When the leaf drops continued, Selby staff decided the risk of waiting was too great.</p><p><b>Saving the trees</b></p><p>The treatment was not simple, though.</p><p>Insecticide leaf sprays were impractical for such large trees with so many leaves, and the benefits are short-lived. Leaching the chemicals down to the tree roots could contaminate the soil and Sarasota Bay.</p><p>An attempt to inject treatments directly into the trunks failed. Ficus sap is highly pressurized; the trees spit out their medicine like a sick child.</p><p>McLaughlin shifted to a concentrated spray, applying it in measured amounts to the tree trunks. The chemicals absorb through the bark.</p><p>So far, so good, he says.</p><p>McLaughlin gathered a handful of fallen leaves and examined them under a hand-held microscope recently. None had signs of infestation.</p><p>A healthy leaf canopy has returned over the last few months.</p><p>The treatment should keep the ficus whitefly at bay for a year or more. What happens after that is hard to say.</p><p>The infestation could return. More treatments may be inevitable. Or the pest could become less pervasive, with predators taking notice and a natural balance settling in.</p><p>Selby has the expertise and resources to keep the pest in check. McLaughlin's long-term prognosis for the trees is good.</p><p>"I bet they'll outlive us," he said.</p><p>Homeowners may have a more difficult time saving their trees. </p><p>Selby donors stepped up to cover the cost of treatments, which ran into the thousands of dollars. </p><p>"There are systemic insecticides that work fairly well on the ficus whitefly but if the homeowner has a few trees or a long hedge it can become difficult for them to afford," Mannion said.</p><p>Mannion is doing research to identify the whiteflies' natural predators and other treatment methods.</p><p>"There's a statewide effort," she said. "But it takes time."</p><p><empty></p>